The present invention relates to a method of manufacturing a steel plate with a seal coating for a steel laminate gasket. Further, the present invention disclosed a method of manufacturing a steel laminate gasket with a seal coating between steel plates.
A steel laminate gasket is formed of a plurality of steel plates stacked one after another. In one of a steel laminate type cylinder head gasket, for example, sealing means is provided around cylinder bores and holes for oil and water of the gasket to seal around the bores and holes, while in some of a steel laminate type cylinder head gasket, a plurality of steel plates is simply stacked together without using any sealing means around the cylinder bores and holes for oil and water.
The steel laminate gasket is situated between two engine parts and is tightened strongly in use. However, if sealing means is not provided around the cylinder bores and holes for oil and water, fluid may leak therefrom by passing between the steel plates. Especially, since tightening pressure around the holes for oil and water is not strong, water and oil are liable to leak around the holes for oil and water. Namely, the gasket can not provide sufficient sealing, and leakage causes corrosion of a gasket.
In order to prevent leakage around water and oil holes, it was proposed that a seal coating is formed between two steel plates. The seal coating may be provided on one of two steel plates facing with each other or both sides of the steel plates. The seal coating must be even in thickness to properly seal between the two steel plates.
One method of forming a steel plate with a seal coating is that a seal coating is formed on one or both entire sides of a base plate, and then the base plate is pressed or cut to thereby form a complete steel plate. In this method, the seal coating material is applied on the entire surface of the base plate. Namely, the seal coating is applied onto an area of the base plate which is not used for a steel plate of a gasket. In some situations, about 50% of the base plate is used for the steel plates of a gasket, and the rest of the base plate is discarded. Since the coating material is expensive,the method of coating the coating material on the entire surface of the base plate is costly.
Another method of forming a steel plate with a seal coating is that a base plate is, at first, cut into the actual configuration of the steel plate, and the coating is applied thereon. In case the steel plate is formed by cutting the base plate, the steel plate is slightly deformed. Therefore, it is very difficult to coat the coating material with even thickness. Further, the coating material is liable to accumulate around edge portions of the steel plate. As a result, it is very difficult to apply onto the steel plate a seal coating with even thickness.
Accordingly, one object of the present invention is to provide a method of manufacturing a steel plate with a seal coating, wherein a seal coating can be formed on a steel plate with a minimum amount of a coating material.
Another object of the invention is to provide a method of manufacturing a steel plate as stated above, wherein a seal coating can be evenly applied onto a steel plate.
A further object of the invention is to provide a method of manufacturing a steel laminate gasket with a seal coating between steel plates, which can be easily and economically made.
A still further object of the invention is to provide a method of manufacturing a steel laminate gasket as stated above, wherein the sealing ability of the gasket is excellent.
Further objects and advantages of the invention will be apparent from the following description of the invention.